I need assistance solving this for Algebra 2: 9 + ex = 12 solve

To ? nd out how many students are unhappy with the dining hall food, you distribute a survey. which method of surveying would produce the least amount of bias in your data?

The quadratic function h(t) = -16.1t^2 + 150 models a balls height, in feet, over time, in seconds, after its dropped from a 15 story building. from what height in feet was the ball dropped?

Researchers were interested in whether relaxation training decreases the number of headaches a person experiences. they randomly assigned 20 participants to a control group or a relaxation training group and noted the change in number of headaches each group reported from the week before training to the week after training. which statistical analysis should be performed to answer the researchers' question?